Commit f2814caaf04fc041a028d5ede4fb4db5ee2f19ae | zig

author	Matthew Lugg <mlugg@mlugg.co.uk> 2023-10-24 05:16:49+01:00
committer	Matthew Lugg <mlugg@mlugg.co.uk> 2023-10-24 14:28:34+01:00
log	f2814caaf04fc041a028d5ede4fb4db5ee2f19ae
tree	50dfaa41d3118225cf1d3da6b31d637e657792bf
parent	67caf685056bcdbbe4e696cada927615b0dd6fe9
signature	Commit is signed but in an unrecognized format.

Sema: don't allow undef values through resolveDefinedValue in typeof block

This logic is not correct in most cases. If any instruction needs to
operate with different semantics within `@TypeOf`, it should be made to
do so explicitly.

This broke a line in `std.mem`: I have opted to fix this in std for now,
since as far as I know it's not yet been discussed which operations (if
any) should be special-cased like this within `@TypeOf`.

2 files changed, 7 insertions(+), 2 deletions(-)

lib
- std
  - mem.zig
src
- Sema.zig

lib/std/mem.zig+7-1

...	...	@@ -3666,7 +3666,13 @@ fn ReverseIterator(comptime T: type) type {
3666	3666	@compileError("expected slice or pointer to array, found '" ++ @typeName(T) ++ "'");
3667	3667	};
3668	3668	const Element = std.meta.Elem(Pointer);
3669		const ElementPointer = @TypeOf(&@as(Pointer, undefined)[0]);
	3669	const ElementPointer = @Type(.{ .Pointer = ptr: {
	3670	var ptr = @typeInfo(Pointer).Pointer;
	3671	ptr.size = .One;
	3672	ptr.child = Element;
	3673	ptr.sentinel = null;
	3674	break :ptr ptr;
	3675	} });
3670	3676	return struct {
3671	3677	ptr: Pointer,
3672	3678	index: usize,

src/Sema.zig-1

...	...	@@ -2104,7 +2104,6 @@ fn resolveDefinedValue(
2104	2104	const mod = sema.mod;
2105	2105	const val = try sema.resolveValue(air_ref) orelse return null;
2106	2106	if (val.isUndef(mod)) {
2107		if (block.is_typeof) return null;
2108	2107	return sema.failWithUseOfUndef(block, src);
2109	2108	}
2110	2109	return val;